VTA and SRA?

same thingie

They are the same thing. VTA = vertical tracking angle; SRA = stylus rake angle. Both are measures of the angle of the stylus to the groove along the axis of the cantilever. The measure of the angle of the stylus to the groove perpendicular to the axis of the cantilever is called azimuth. Hope this helps.

Scroll about 2/3rds of the way down the page.

http://www.vinylzone.com/cartalign.asp

Here's another excellent article:

http://www.theabsolutesound.com/articles/setting-up-a-phono-cartridge/

Mofimadness,Thanks!
Yogiboy

Yogiboy,
There's lots of stuff recently posted here on Audiogon (search SRA if you want to know more).

The vinylzone link is mostly a simple and straightforward explanation of the terms.

The other one, from Absolute sound, is confusing and vague, and the author appears to not have looked into the subject thoroughly, as he has to tweak his responses to comments from others.

His view on anti-skate (he doesn't use it) also begs the question of how far he has looked into things and the consequences (to his stylus and records) of his decision.

Thanks JG!

They are absolutely NOT the same thing. I started the following thread right here on Audiogon -- long before M. Fremer figured it out by the way;~):
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1140840022&openmine&Nsgarch&4&5&st0

Unfortunately, my IP doesn't support my picture files anymore. Sorry.
.

Czarivey and Effischer,

Your posts are incorrect. For a basic understanding read the link posted by Mofimadness above, which is *almost* correct.

VTA and SRA are both viewed from the side of the cartridge (along the axis of the cantilever, as Effischer put it) but that's where the similarity ends.

VTA = the angle formed between:
1) the horizontal surface of the record and
2) a line extended from the point of the stylus through the axis of vertical rotation of the cantilever (this would be the same as the line of the cantilever, except for the offset provided by the height of the stylus).

VTA's range from 15-25 degrees, with 20 degrees being the industry standard since the mid-1960s.

SRA = the angle formed between:
1) a vertical line through the lowest contact point of the stylus and
2) the line of the stylus's contact ridge or edge.

SRA's on elliptical, line contact, micro-ridge and cutting styli tend to be 1-2 degrees forward from vertical, but there is no industry standard. A conical stylus can be said to have no SRA. Its spherical contact surface results in a single contact point, so there's no contact ridge or edge to measure.

As can be seen, VTA and SRA are very different.

Here we go again.
And I was no fan of Ronald Reagan.

I stand corrected. So, presuming I now understand this, SRA is a fixed relationship within the stylus itself and cannot be adjusted.

Read it again.

SRA = the angle formed between:
1) a vertical line through the lowest contact point of the stylus and
2) the line of the stylus's contact ridge or edge.

#1 never changes, but #2 can be changed in several ways.

The stylus's contact edge can be tilted forward or back by altering the height of the tonearm. It also changes as a side-effect of any alteration in downforce (VTF). Your own tonearm (listed as a Graham Phantom Supreme) has these adjustments.

You also change SRA (inadvertently) virtually every time you change LP's, since different LP's have different thicknesses.

Dougdeacon,so if I change the SRA by adjusting the height of the tonearm the VTA is not changed?

Both would be changed.

Changing SRA without simultaneously changing VTA would require altering the angle between the stylus and cantilever... not recommended. ;-)

So, SRA can only be indirectly altered by means of adjusting VTA and / or VTF. Could be why I never bothered to look any further than VTA. BTW, VTA adjustment on the fly is the main reason I went with the Graham. Learned this a long, long time ago with my Magnepan Unitrac I.

If the ideal VTA is 20 degrees off the horizontal, then I assume the ideal SRA is 20 degrees off the vertical, correct?

1-2 degrees, not 20 degrees.

the most normal horizontal angle, is 20-22 degrees

^^ No. Assuming the LP is flat, absolutely vertical is 90 degrees. Because the cutterhead that made the LP has to be angled slightly, the playback stylus is too. This is generally about 2 degrees, but must be considered an approximation, as it is never exactly 2 degrees off of vertical with the cutterhead.

I imagine that people having difficulty understanding this also find it difficult to visualize other spatial relationships. They may be challenged by geometry, geography, map-reading and navigation, jigsaw puzzles, loading the dishwasher efficiently, assembling a machine from an exploded diagram, etc.

Quiz: most people can draw a rough map of Italy or Michigan from memory. How many can do the same for France or Maryland?

Well, I'm a mathematician so I'm certainly not challenged by geometry but I am challenged to measure 1 or 2 degrees angle on something I can barely see.

Not trying to be dense here but the articles above from TAS and vinyl zone seem to contradict each other on SRA.

The first shows SRA measured off a line running along the back edge of the stylus while the second says it is off a line running through the vertical axis of the stylus.

Whether SRA is worth measuring is another question altogether, one that's been discussed to death on many threads.

My own view is that while I can measure SRA on most styli I choose not to, since I've found it to be a waste of time. SRA differs from record to record, as Atmasphere just noted, so the best way to set it is by ear. Adjust as little or as often as one's ears and listening preferences require.

***
The vinyl zone and TAS definitions do contradict, and neither is correct. That's why I posted that the vinyl zone article was "almost" correct.

Re-read my SRA definition above.

Ah, now I get it. Thanks Doug! As always we can count on you to sort out the confusion.

If your tonearm does not have VTA adjustment on the fly, using a USB computer magnifier scope and overlaying the stylus image over protractor software and adjust the SRA to 92 degrees is a good start.

Here is another very good explanation of VTA/SRA (updated from an older article):

http://www.hi-fiworld.co.uk/index.php/vinyl-lp/37-technology/73-vertical-tracking-angle.html

And here is one on tonearm geometry:

http://www.hi-fiworld.co.uk/index.php/vinyl-lp/37-technology/71-arm-geometry.html